1. Field of the Invention
The present invention relates to a lens barrel that has a configuration in which cylindrical members are coupled through cam coupling to cause the above cylindrical members to relatively move in an optical axis direction.
2. Description of the Related Art
Lens barrels used in photographing devices such as cameras for shooting photographs have been configured by a plurality of optical lenses or the like, and a plurality of barrel members or the like each holding the plurality of optical lenses and formed in an annular or cylindrical shape. In addition, the plurality of barrel members are configured in such a manner as to be coupled with each other through cam coupling or the like. With such a configuration, the above individual barrel members can relatively move in an optical axis direction to achieve, for example, zooming operation (variable power operation), and focusing operation (focus adjusting operation).
For example, a lens barrel disclosed by Japanese Patent Application Laid-Open Publication No. 11-174305 includes a barrel cam on which a pair of cam grooves are formed and a barrel member provided with pair of cam followers corresponding to the above pair of cam grooves. The lens barrel is configured such that one of the above pair of cam grooves engages with one of the above pair of cam followers, the one cam follower moves in the above one cam groove to cause the above barrel member to move in a first region, the other one of the above pair of cam grooves engages with the other one of the above pair of cam followers, and the other cam follower moves in the above other cam groove to cause the above barrel member to move in a second region.
In addition, cameras or the like (photographing devices) to which this kind of lens barrel applies are those which a user readily carries about and takes out to use at any desired time.
A lens barrel disclosed by Japanese Patent Application Laid-Open Publication No. 2009-258295 or the like includes a first barrel member, on which at least two metal cam pins and at least two resin cam pins are disposed alternately in a circumferential direction on the same circumferential face, and a second barrel member that has cam paths each having the same shape and has a plurality of cam grooves to correspondingly engage with the above metal cam pins and the above resin cam pins, and that can move relatively to the above first barrel member.
In recent years, cameras or the like (photographing devices) to which this kind of lens barrel applies have experienced an increase in zoom magnification (variable power ratio), and for example, photographing devices having an optical zooming function of 10× to 20× magnifications have generally come into practical and widespread use.